The NS6 and NS4 Series Smoke Detector Base Series is designed specifically for use with HOCHIKI NS Conventional Models SIJ- 24 Ionization Smoke Detector, SLR-24V Photoelectric Smoke Detector, SLR-24H Photoelectric with Heat Smoke Detector, SLR- 835 Photoelectric Smoke Detector, or DCD-135/190 Fixed Temperature/Rate-of-Rise Heat Detector. The NS6 Base is an electronics free 6" base featuring a plastic tamper-lock lug. Each base is equipped with a resistor. Refer to the chart (left) for additional specifications. The NS4 base is a 4" version of the NS6 base.